Search

Campylobacter was considered asaccharolytic, but is now known to carry saccharide metabolization pathways for L-fucose and d-glucose. We hypothesized that these clusters are beneficial for Campylobacter niche adaptation and may help establish human infection. We investigated the distribution of d-glucose and L-fucose clusters among ∼9600 C. jejuni and C. coli genomes of different isolation sources in the Netherlands, the United Kingdom, the United States of America and Finland. The L-fucose utilization cluster was integrated at the same location in all C. jejuni and C. coli genomes, and was flanked by the genes rpoB, rpoC, rspL, repsG and fusA, which are associated with functions in transcription as well as translation and in acquired drug resistance. In contrast, the flanking regions of the d-glucose utilization cluster were variable among the isolates, and integration sites were located within one of the three different 16S23S ribosomal RNA areas of the C. jejuni and C. coli genomes. In addition, we investigated whether acquisition of the L-fucose utilization cluster could be due to horizontal gene transfer between the two species and found three isolates for which this was the case: one C. jejuni isolate carrying a C. coli L-fucose cluster, and two C. coli isolates which carried a C. jejuni L-fucose cluster. Furthermore, L-fucose utilization cluster alignments revealed multiple frameshift mutations, most of which were commonly found in the non-essential genes for L-fucose metabolism, namely, Cj0484 and Cj0489. These findings support our hypothesis that the L-fucose cluster was integrated multiple times across the C. coli/C. jejuni phylogeny. Notably, association analysis using the C. jejuni isolates from the Netherlands showed a significant correlation between human C. jejuni isolates and C. jejuni isolates carrying the L-fucose utilization cluster. This correlation was even stronger when the Dutch isolates were combined with the isolates from the UK, the USA and Finland. No such correlations were observed for C. coli or for the d-glucose cluster for both species. This research provides insight into the spread and host associations of the L-fucose and d-glucose utilization clusters in C. jejuni and C. coli, and the potential benefits in human infection and/or proliferation in humans, conceivably after transmission from any reservoir., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Campylobacteriosis, primarily caused by Campylobacter jejuni and C. coli, is the main bacterial zoonosis worldwide. While poultry is recognized as the main reservoir, bovines are considered another important reservoir for Campylobacter spp. found in human infections. In contrast to chicken, retail beef is seldom contaminated by Campylobacter species. However, beef liver is recognized to be frequently contaminated and has been linked to human infections via epidemiological investigations. Our aims were to evaluate the prevalence of Campylobacter spp. inside and on the surface of beef liver pieces at retail in Finland and to analyse the population in more detail using whole genome sequencing (WGS) to assess the public health relevance. A total of 90 retail beef livers were studied using both enrichment of the external peptone-saline rinse of the liver piece and direct culture from the inside after surface sterilization. Furthermore, 46 of the livers were also studied using direct culture of retail beef liver juice collected from the bottom of the consumer package to estimate the concentration of Campylobacter species. Overall, 44 (49 %) of the samples were positive for Campylobacter species, C. jejuni, C. fetus and C. lari being identified in 42 %, 8.9 % and 1.1 % of the samples, respectively. Direct culture of retail liver juice was a sensitive and convenient method for Campylobacter spp. detection, resulting in 48 % prevalence and a mean concentration of 49 cfu/ml (maximum 335 cfu/ml). Two samples (2.2 %), containing large hepatic ducts, were positive for C. jejuni internally, representing multilocus sequence typing (MLST) sequence type ST-19 and ST-21. WGS, core genome phylogeny and core genome MLST revealed that in most cases only one clearly distinct clone of clinically relevant C. jejuni or C. fetus was isolated from a single lot of samples. However, in some cases several distinct clones were identified simultaneously even from a single liver piece. In epidemiological investigations, it is thus highly advisable to genotype multiple isolates to capture the whole diversity of Campylobacter spp. from suspected food sources. Good kitchen hygiene, avoidance of cross-contamination and thorough cooking are important for limiting the transmission of campylobacteriosis., Competing Interests: Declaration of competing interest None., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Poultry are considered a major reservoir and source of human campylobacteriosis, but the roles of environmental reservoirs, including wild birds, have not been assessed in depth. In this study, we isolated and characterized Campylobacter jejuni from western jackdaws ( n = 91, 43%), mallard ducks ( n = 82, 76%), and pheasants ( n = 9, 9%). Most of the western jackdaw and mallard duck C. jejuni isolates represented multilocus sequence typing (MLST) sequence types (STs) that diverged from those previously isolated from human patients and various animal species, whereas all pheasant isolates represented ST-19, a common ST among human patients and other hosts worldwide. Whole-genome MLST revealed that mallard duck ST-2314 and pheasant ST-19 isolates represented bacterial clones that were genetically highly similar to human isolates detected previously. Further analyses revealed that in addition to a divergent ClonalFrame genealogy, certain genomic characteristics of the western jackdaw C. jejuni isolates, e.g., a novel cdtABC gene cluster and the type VI secretion system (T6SS), may affect their host specificity and virulence. Game birds may thus pose a risk for acquiring campylobacteriosis; therefore, hygienic measures during slaughter and meat handling warrant special attention. IMPORTANCE The roles of environmental reservoirs, including wild birds, in the molecular epidemiology of Campylobacter jejuni have not been assessed in depth. Our results showed that game birds may pose a risk for acquiring campylobacteriosis, because they had C. jejuni genomotypes highly similar to human isolates detected previously. Therefore, hygienic measures during slaughter and meat handling warrant special attention. On the contrary, a unique phylogeny was revealed for the western jackdaw isolates, and certain genomic characteristics identified among these isolates are hypothesized to affect their host specificity and virulence. Comparative genomics within sequence types (STs), using whole-genome multilocus sequence typing (wgMLST), and phylogenomics are efficient methods to analyze the genomic relationships of C. jejuni isolates., (Copyright © 2019 American Society for Microbiology.)

Unlabelled: Despite the importance of lipooligosaccharides (LOSs) in the pathogenicity of campylobacteriosis, little is known about the genetic and phenotypic diversity of LOS in Campylobacter coli In this study, we investigated the distribution of LOS locus classes among a large collection of unrelated C. coli isolates sampled from several different host species. Furthermore, we paired C. coli genomic information and LOS chemical composition for the first time to investigate possible associations between LOS locus class sequence diversity and biochemical heterogeneity. After identifying three new LOS locus classes, only 85% of the 144 isolates tested were assigned to a class, suggesting higher genetic diversity than previously thought. This genetic diversity is at the basis of a completely unexplored LOS structural heterogeneity. Mass spectrometry analysis of the LOSs of nine isolates, representing four different LOS classes, identified two features distinguishing C. coli LOS from that of Campylobacter jejuni 2-Amino-2-deoxy-d-glucose (GlcN)-GlcN disaccharides were present in the lipid A backbone, in contrast to the β-1'-6-linked 3-diamino-2,3-dideoxy-d-glucopyranose (GlcN3N)-GlcN backbone observed in C. jejuni Moreover, despite the fact that many of the genes putatively involved in 3-acylamino-3,6-dideoxy-d-glucose (Quip3NAcyl) were apparently absent from the genomes of various isolates, this rare sugar was found in the outer core of all C. coli isolates. Therefore, regardless of the high genetic diversity of the LOS biosynthesis locus in C. coli, we identified species-specific phenotypic features of C. coli LOS that might explain differences between C. jejuni and C. coli in terms of population dynamics and host adaptation., Importance: Despite the importance of C. coli to human health and its controversial role as a causative agent of Guillain-Barré syndrome, little is known about the genetic and phenotypic diversity of C. coli LOSs. Therefore, we paired C. coli genomic information and LOS chemical composition for the first time to address this paucity of information. We identified two species-specific phenotypic features of C. coli LOS, which might contribute to elucidating the reasons behind the differences between C. jejuni and C. coli in terms of population dynamics and host adaptation., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Campylobacter jejuni is the leading cause of bacterial gastroenteritis and chicken is considered a major reservoir and source of human campylobacteriosis. In this study, we investigated temporally related Finnish human (n=95), chicken (n=83) and swimming water (n=20) C. jejuni isolates collected during the seasonal peak in 2012 using multilocus sequence typing (MLST) and whole-genome MLST (wgMLST). Our objective was to trace domestic human C. jejuni infections to C. jejuni isolates from chicken slaughter batches and swimming water. At MLST level, 79% of the sequence types (STs) of the human isolates overlapped with chicken STs suggesting chicken as an important reservoir. Four STs, the ST-45, ST-230, ST-267 and ST-677, covered 75% of the human and 64% of the chicken isolates. In addition, 50% of the swimming water isolates comprised ST-45, ST-230 and ST-677. Further wgMLST analysis of the isolates within STs, accounting their temporal relationship, revealed that 22 of the human isolates (24%) were traceable back to C. jejuni positive chicken slaughter batches. None of the human isolates were traced back to swimming water, which was rather sporadically sampled. The highly discriminatory wgMLST, together with the patient background information and temporal relationship data with possible sources, offers a new, accurate approach to trace back the origin of domestic campylobacteriosis. Our results suggest that potentially a substantial proportion of campylobacteriosis cases during the seasonal peak most probably are due to other sources than chicken meat consumption. These findings warrant further wgMLST-based studies to reassess the role of other reservoirs in the Campylobacter epidemiology both in Finland and elsewhere., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In recent years, increasing numbers of consumers have become interested in feeding raw food for their pet dogs as opposed to commercial dry food, in the belief of health advantages. However, raw meat and internal organs, possibly contaminated by pathogens such as Campylobacter spp., may pose a risk of transmission of zoonoses to the pet owners. Campylobacter jejuni is the leading cause of bacterial gastroenteritis in humans but C. upsaliensis has also been associated with human disease. In this study we investigated the effect of different feeding strategies on the prevalence of Campylobacter spp. in Finnish dogs. We further characterized the isolates using multilocus sequence typing (MLST), whole-genome (wg) MLST and antimicrobial susceptibility testing. Dogs were sampled before and after a feeding period consisting of commercial raw feed or dry pellet feed. Altogether 56% (20/36) of the dogs yielded at least one Campylobacter-positive fecal sample. C. upsaliensis was the major species detected from 39% of the dogs before and 30% after the feeding period. Two C. jejuni isolates were recovered, both from raw-fed dogs after the dietary regimen. The isolates represented the same genotype (ST-1326), suggesting a common infection source. However, no statistically significant correlation was found between the feeding strategies and Campylobacter spp. carriage. The global genealogy of MLST types of dog and human C. upsaliensis isolates revealed weakly clonal population structure as most STs were widely dispersed. Major antimicrobial resistance among C. upsaliensis isolates was against streptomycin (STR MIC > 4 mg/l). Apart from that, all isolates were highly susceptible against the antimicrobials tested. Mutations were found in the genes rpsL or rpsL and rsmG in streptomycin resistant isolates. In conclusion, increasing trend to feed dogs with raw meat warrants more studies to evaluate the risk associated with raw feeding of pets in transmission of zoonoses to humans.

A total of 95 human Campylobacter jejuni isolates acquired from domestic infections and collected from three districts in Finland during the seasonal peak (June to September) in 2012 were analyzed by PCR-based multilocus sequence typing (MLST) and by whole-genome sequencing (WGS). Four predominant sequence types (STs) were detected among the isolates: ST-45 (21%) and ST-230 (14%, ST-45 clonal complex [CC]), ST-267 (21%, ST-283 CC), and ST-677 (19%, ST-677 CC). In districts 1 and 3, most of the infections occurred from early July to the middle of August, with a peak at weeks 29 to 31, but in district 2, the infections were dispersed more evenly throughout 3 months (June to August). WGS data were used for further whole-genome MLST (wgMLST) analyses of the isolates representing the four common STs. Shared loci of the isolates within each ST were analyzed as distance matrices of allelic profiles by the neighbor-net algorithm. The highest allelic variations (>400 different alleles) were detected between different clusters of ST-45 isolates (1,121 shared loci), while ST-230 (1,264 shared loci), ST-677 (1,169 shared loci), and ST-267 isolates (1,217 shared loci) were less diverse with the clusters differing by <40 alleles. Closely related isolates showing no allelic variation (subclusters) were detected among all four major STs. In some cases, they originated from different districts, suggesting that isolates can be epidemiologically connected and may have the same infection source despite being originally identified as sporadic infections., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Background: Waterborne Campylobacter jejuni outbreaks are common in the Nordic countries, and PFGE (pulsed field gel electrophoresis) remains the genotyping method of choice in outbreak investigations. However, PFGE cannot assess the clonal relationship between isolates, leading to difficulties in molecular epidemiological investigations. Here, we explored the applicability of whole genome sequencing to outbreak investigation by re-analysing three C. jejuni strains (one isolated from water and two from patients) from an earlier resolved Finnish waterborne outbreak from the year 2000., Results: One of the patient strains had the same PFGE profile, as well as an identical overall gene synteny and three polymorphisms in comparison with the water strain. However, the other patient isolate, which showed only minor differences in the PFGE pattern relative to the water strain, harboured several polymorphisms as well as rearrangements in the integrated element CJIE2. We reconstructed the genealogy of these strains with ClonalFrame including in the analysis four C. jejuni isolated from chicken in 2012 having the same PFGE profile and sequence type as the outbreak strains. The three outbreak strains exhibited a paraphyletic relationship, implying that the drinking water from 2000 was probably contaminated with at least two different, but related, C. jejuni strains., Conclusions: Our results emphasize the capability of whole genome sequencing to unambiguously resolve the clonal relationship between isolates of C. jejuni in an outbreak situation and evaluate the diversity of the C. jejuni population.

Aim: To elucidate the Campylobacter jejuni population in organically farmed laying hens in Finland, multilocus sequence typing (MLST) was combined with characterization of clustered regularly interspaced short palindromic repeat (CRISPR) sequences., Methods and Results: A total of 147 Camp. jejuni isolates, collected from organically farmed laying hens from 18 farms in 2003-2004, were previously analysed by pulsed-field gel electrophoresis. In the present study, subsets of the isolates were further analysed by MLST and CRISPR sequences. Fourteen STs were found by MLST. ST-50 (27%, 7/18 farms), ST-3272 (20%, 8/18 farms), ST-45 (12%, 7/18 farms) and ST-356 (12%, 5/18 farms) were the most common STs. CRISPR types were identical among all isolates of ST-50 (ST-21 clonal complex (CC)) and the most variable among ST-45 (ST-45 CC)., Conclusions: ST-3272 (UA), a common ST in this study, has been infrequently detected in other hosts. Other major STs (ST-50 and ST-45) have been common in several hosts such as conventional poultry and bovines. CRISPR typing provided additional discrimination between isolates of certain dominant STs and could be useful in further epidemiological studies., Significance and Impact of the Study: This study gives new information about MLST and CRISPR types of Camp. jejuni among organically farmed laying hens., (© 2014 The Society for Applied Microbiology.)

Campylobacter jejuni is a highly diverse enteropathogen that is commonly detected worldwide. It can sometimes cause bacteraemia, but the bacterial characteristics facilitating bloodstream infection are not known. A total of 73 C. jejuni isolates, consecutively collected from blood-borne infections during a 10-year period all over Finland and for which detailed clinical information of the patients were available, were included. We screened the isolates by PCR for the lipooligosaccharide (LOS) locus class and for the presence of the putative virulence genes ceuE, ciaB, fucP, and virB11. The isolates were also tested for γ-glutamyl transpeptidase production. The results were analysed with respect to the clinical characteristics of the patients, and the multilocus sequence types (MLSTs) and serum resistance of the isolates. LOS locus classes A, B, and C, which carry genes for sialylation of LOS, were detected in only 23% of the isolates. These isolates were not more resistant to human serum than those with the genes of non-sialylated LOS locus classes, but were significantly more prevalent among patients with underlying diseases (p 0.02). The fucose permease gene fucP was quite uncommon, but was associated with the isolates with the potential to sialylate LOS (p <0.0001). LOS locus classes and some of the putative virulence factors were associated with MLST clonal complexes. Although some of the bacterial characteristics studied here have been suggested to be important for the invasiveness of C. jejuni, they did not explain why the clinical isolates in the present study were able to cause bacteraemia., (© 2013 The Authors Clinical Microbiology and Infection published by John Wiley and Sons on behalf of the European Society of Clinical Microbiology and Infectious Diseases.)

Campylobacter jejuni bacteria are highly diverse enteropathogens. Seventy-three C. jejuni isolates from blood collected in Finland were analyzed by multilocus sequence typing and serum resistance. Approximately half of the isolates belonged to the otherwise uncommon sequence type 677 clonal complex. Isolates of this clonal complex were more resistant than other isolates to human serum.

In this study, we investigated the multilocus sequence type (MLST) diversity and population genetics of Campylobacter jejuni isolates collected from the natural waters (n = 57), wild birds (n = 37) and zoo animals (n = 19) in southern Finland, the Helsinki area and the Helsinki Zoo, respectively. On average, we found C. jejuni in 20%, 10.4% or 11.5% of the samples collected from natural waters, wild birds and zoo animals, respectively. High ST diversity was detected in all three sources and 41.2% of the STs were novel, but the multi-host adapted ST-45 was the most common ST detected. The MLST data, supplemented with C. jejuni isolates from domestically acquired human infections (n = 454), poultry (n = 208) and bovines (n = 120), were utilized in a population structure study. The results indicate four groups of strains with varying ecological associations, demonstrating presence of genetically distinct lineages within each of the studied sources. We discovered that the greatest ST overlap occurs between human isolates and isolates from natural waters and poultry, which suggests that the latter two are the most important sources of C. jejuni among domestically acquired infections in Finland., (© 2012 Blackwell Verlag GmbH.)

We sought to explain seasonality and other aspects of Campylobacter jejuni epidemiology by integrating population genetic and epidemiological analysis in a large 3-year longitudinal, two-centre, population-based study. Epidemiological information was collected for 1505 isolates, which were multilocus sequence-typed. Analyses compared pathogen population structure between areas, over time, and between clinical presentations. Pooled analysis was performed with published international datasets. Subtype association with virulence was not observed. UK sites had nearly identical C. jejuni populations. A clade formed by ST45 and ST283 clonal complexes showed a summer peak. This clade was common in a Finnish dataset but not in New Zealand and Australian collections, countries with less marked seasonality. The UK, New Zealand and Australian collections were otherwise similar. These findings map to known in-vitro differences of this clade. This identifies a target for studies to elucidate the drivers of the summer peak in human C. jejuni infection.

The lipooligosaccharide (LOS) locus class was determined using polymerase chain reaction (PCR) in 335 Finnish Campylobacter jejuni strains isolated from humans, poultry and bovines with known multilocus sequence types. The results revealed an association between clonal complexes/sequence types (STs) and LOS locus classes. Based on these results, we further predicted the LOS locus classes distribution among the STs of 209 additional C. jejuni strains from Finnish human domestically acquired infections. Non-sialylated LOS locus classes were associated with STs that comprised ≈55% of patient strains. Sialylated LOS locus classes A and B were associated with STs infrequently isolated, whereas class C was correlated with the ST-21 complex, found in ≈14% of human strains. A combination of the LOS locus class and multilocus sequence type may provide new information on the epidemiology and association of C. jejuni strains with certain disease outcomes.

The genetic diversity of Campylobacter jejuni strains isolated from Finnish patients was studied by typing 508 strains by pulsed-field gel electrophoresis: 311 were isolated from domestically acquired infections and 197 from travel-related infections. The strains were systematically selected from a larger collection of previously serotyped strains isolated during two 1-year sampling periods. The four most common SmaI profiles accounted for 45% of the domestic strains but only 3% of the travel-related strains. Of the domestic strains, 69% belonged to SmaI subtypes found during both sampling periods. The predominating SmaI subtypes and strains that were not digested by SmaI were typed by KpnI. Analyzing the temporal diversity of the pulsed-field gel electrophoresis profiles revealed six common persistent SmaI/KpnI subtypes among the domestic strains. Five of them have been identified in cattle, and two in chickens with a temporal association with human infections.

Background: Campylobacter bacteremia is an uncommon condition, usually diagnosed in elderly and immunocompromised patients., Methods: Blood culture isolates and clinical information were collected for patients with diagnoses of Campylobacter jejuni or Campylobacter coli bacteremia in Finland from 1998 through 2007. Bacterial species were identified by means of polymerase chain reaction analysis, and minimal inhibitory concentrations for ciprofloxacin, clindamycin, doxycycline, erythromycin, gentamicin, meropenem, and metronidazole were determined with an agar dilution method. Medical records and mortality data within 1 year after the bacteremic episode were reviewed., Results: The study included 76 patients (median age, 46 years), for whom bacterial isolates (C. jejuni in 73, C. coli in 3) and clinical information were available. Most patients (70%) had no significant underlying diseases. The majority (82%) of the isolates were susceptible for all antimicrobial agents tested. However, antimicrobial therapy seemed to have only a limited effect, because no differences could be detected between patients with appropriate empirical antimicrobial treatment and those with delayed appropriate, inappropriate, or no antimicrobial therapy, either in the duration of hospitalization (median, 4 days for both groups) or in attributable mortality. The outcome of the infection was severe in 4 patients infected with C. jejuni; 2 died within 30 days, spondylodiscitis developed in 1, and Guillain-Barré syndrome developed in 1., Conclusions: C. jejuni and C. coli bacteremia occurred mainly in moderately young individuals without severe underlying diseases. The bacterial isolates were predominantly susceptible to antimicrobial agents, and the outcome of the disease was typically good, regardless of appropriate or inappropriate antimicrobial treatment given in the hospital.

Objectives: To assess the occurrence, clinical picture, and triggering infections of reactive arthritis (ReA) associated with a large waterborne gastroenteritis outbreak., Methods: After an extensive sewage contamination of the water supply system, an estimated 8453 of the 30 016 inhabitants of the town of Nokia fell ill. General practitioners and occupational physicians were advised to refer any patients with suspicion of new ReA to rheumatological examination including faecal culture, human leucocyte antigen (HLA)-B27 and antibody tests for Campylobacter, Salmonella, and Yersinia., Results: Forty-five patients (33 females, 12 males) aged 16-77 years (median 53) were referred. ReA was diagnosed in 21, postinfectious arthralgia in 13, and other musculoskeletal conditions in 11 patients. HLA-B27 was positive in five out of 44 patients (11%). Of the 21 patients with ReA, possible triggering infections were observed in seven (33%), Campylobacter in four, Yersinia in three, and Salmonella in one, who also had Campylobacter infection. ReA was mild in all but one patient who presented with persistent Salmonella enterica serotype enteritidis infection., Conclusions: Taking into account the large population contaminated with potentially arthritogenic agents, the occurrence of ReA was rare and mild in character.

We describe the long-term multilocus sequence typing (MLST) analysis of the population structure and dynamics of 454 Finnish human Campylobacter jejuni isolates, as well as 208 chicken isolates, collected during the mid-1990s to 2007. The sequence type clonal complexes (ST CC) ST-45 CC, ST-21 CC, and ST-677 CC were the most common ones found among all isolates, and they covered 73.9% of all isolates. The ST-283 CC also was found frequently among chicken isolates (8.2%). The predominant STs among all isolates were ST-45, ST-50, and ST-677. ST-137 and ST-230 were common among human isolates, and ST-267 was found more frequently among chicken isolates than human isolates. The ST-45 CC was significantly associated with chicken isolates (P < 0.01), whereas the ST-21 CC was associated with human isolates (P < 0.001). The ST-677 CC was not associated with any host (P = 0.5), and an opposite temporary trend of this complex was seen among chicken and human isolates, with an increase in the former and a decrease in the latter during the study period. Furthermore, the ST-22 and ST-48 CCs were significantly associated with human isolates (P < 0.01), but neither of the CCs was found in chicken isolates. The annual overlap between STs from human and chicken isolates decreased from 76% at the beginning of the study to 58% at the end. Our results suggest that the importance of chicken as a reservoir for strains associated with human infections has declined despite the consumption of domestic chicken meat increasing during the follow-up period by 83%.

Background: Campylobacter jejuni is the most common bacterial cause of human gastroenteritis worldwide. Due to the sporadic nature of infection, sources often remain unknown. Multilocus sequence typing (MLST) has been successfully applied to population genetics of Campylobacter jejuni and mathematical modelling can be applied to the sequence data. Here, we analysed the population structure of a total of 250 Finnish C. jejuni isolates from bovines, poultry meat and humans collected in 2003 using a combination of Bayesian clustering (BAPS software) and phylogenetic analysis., Results: In the first phase we analysed sequence types (STs) of 102 Finnish bovine C. jejuni isolates by MLST and found a high diversity totalling 50 STs of which nearly half were novel. In the second phase we included MLST data from domestic human isolates as well as poultry C. jejuni isolates from the same time period. Between the human and bovine isolates we found an overlap of 72.2%, while 69% of the human isolates were overlapping with the chicken isolates. In the BAPS analysis 44.3% of the human isolates were found in bovine-associated BAPS clusters and 45.4% of the human isolates were found in the poultry-associated BAPS cluster. BAPS reflected the phylogeny of our data very well., Conclusions: These findings suggest that bovines and poultry were equally important as reservoirs for human C. jejuni infections in Finland in 2003. Our results differ from those obtained in other countries where poultry has been identified as the most important source for human infections. The low prevalence of C. jejuni in poultry flocks in Finland could explain the lower attribution of human infection to poultry. Of the human isolates 10.3% were found in clusters not associated with any host which warrants further investigation, with particular focus on waterborne transmission routes and companion animals.

In order to compare human and retail poultry meat thermophilic Campylobacter isolates originating in a regional area in Western Finland, minimum inhibitory concentration (MICs) for six antimicrobials (96 isolates) and pulsed-field gel electrophoresis (PFGE) (102 isolates) were analysed. Campylobacter spp. were detected in 10.5% out of 305 fresh poultry products studied; 29 (90.5%) isolates were identified as Campylobacter jejuni. Among the 70 human isolates, 66 (94.3%) isolates were identified as C. jejuni. Only one C. jejuni domestic poultry isolate showed resistance (ampicillin), whereas domestic human C. jejuni isolates were more commonly resistant to ciprofloxacin, nalidixic acid, ampicillin and tetracycline. The resistance in foreign human isolates was significantly more common than among domestic isolates. PFGE analysis with KpnI restriction enzyme resulted in 59 different PFGE types among the poultry and human isolates. Three types were detected first in poultry meat and thereafter during the following month in domestic human samples, whereas the other conjoint types were detected only after many months. This study suggests that poultry products play only a minor role in human campylobacteriosis in the study area and that the resistance found in domestic human isolates is not likely related to retail poultry meat products.

There is a paucity of information regarding antimicrobial agents that are suitable to treat severe infections caused by multidrug-resistant Campylobacter spp. Our aim was to identify agents that are potentially effective against multiresistant Campylobacter strains. The in vitro activities of 20 antimicrobial agents against 238 Campylobacter strains were analyzed by determining MICs by the agar plate dilution method or the Etest. These strains were selected from 1,808 Campylobacter isolates collected from Finnish patients between 2003 and 2005 and screened for macrolide susceptibility by using the disk diffusion test. The 238 strains consisted of 183 strains with erythromycin inhibition zone diameters of < or =23 mm and 55 strains with inhibition zone diameters of >23 mm. Of the 238 Campylobacter strains, 19 were resistant to erythromycin by MIC determinations (MIC > or = 16 microg/ml). Given that the resistant strains were identified among the collection of 1,808 isolates, the frequency of erythromycin resistance was 1.1%. All erythromycin-resistant strains were multidrug resistant, with 18 (94.7%) of them being resistant to ciprofloxacin (MIC > or = 4 microg/ml). The percentages of resistance to tetracycline and amoxicillin-clavulanic acid (co-amoxiclav) were 73.7% and 31.6%, respectively. All macrolide-resistant strains were susceptible to imipenem, meropenem, and tigecycline. Ten (52.6%) multiresistant strains were identified as being Campylobacter jejuni strains, and 9 (47.4%) were identified as being C. coli strains. These data demonstrate that the incidence of macrolide resistance was low but that the macrolide-resistant Campylobacter strains were uniformly multidrug resistant. In addition to the carbapenems, tigecycline was also highly effective against these multidrug-resistant Campylobacter strains in vitro. Its efficacy for the treatment of human campylobacteriosis should be evaluated in clinical trials.

A substantial sampling among domestic human campylobacter cases, chicken process lots, and cattle at slaughter was performed during the seasonal peak of human infections. Campylobacter jejuni isolates (n = 419) were subtyped using pulsed-field gel electrophoresis with SmaI, and isolates representing overlapping types (n = 212) were further subtyped using KpnI for restriction. The SmaI/KpnI profiles of 55.4% (97/175) of the human isolates were indistinguishable from those of the chicken or cattle isolates. The overlapping SmaI/KpnI subtypes accounted for 69.8% (30/43) and 15.9% (32/201) of the chicken and cattle isolates, respectively. The occurrence of identical SmaI/KpnI subtypes with human C. jejuni isolates was significantly associated with animal host species (P < 0.001). A temporal association of isolates from chickens and patients was possible in 31.4% (55/175) of the human infections. Besides chickens as sources of C. jejuni in the sporadic infections, the role of cattle appears notable. New approaches to restrict the occurrence of campylobacters in other farm animals may be needed in addition to hygienic measures in chicken production. However, only about half of the human infections were attributable to these sources.

Background: Campylobacter is the most common cause of bacterial enteritis worldwide. Handling and eating of contaminated poultry meat has considered as one of the risk factors for human campylobacteriosis. Campylobacter contamination can occur at all stages of a poultry production cycle. The objective of this study was to determine the occurrence of Campylobacter during a complete turkey production cycle which lasts for 1,5 years of time. For detection of Campylobacter, a conventional culture method was compared with a PCR method. Campylobacter isolates from different types of samples have been identified to the species level by a multiplex PCR assay., Methods: Samples (N = 456) were regularly collected from one turkey parent flock, the hatchery, six different commercial turkey farms and from 11 different stages at the slaughterhouse. For the detection of Campylobacter, a conventional culture and a PCR method were used. Campylobacter isolates (n = 143) were identified to species level by a multiplex PCR assay., Results: No Campylobacter were detected in either the samples from the turkey parent flock or from hatchery samples using the culture method. PCR detected Campylobacter DNA in five faecal samples and one fluff and eggshell sample. Six flocks out of 12 commercial turkey flocks where found negative at the farm level but only two were negative at the slaughterhouse., Conclusion: During the brooding period Campylobacter might have contact with the birds without spreading of the contamination within the flock. Contamination of working surfaces and equipment during slaughter of a Campylobacter positive turkey flock can persist and lead to possible contamination of negative flocks even after the end of the day's cleaning and desinfection. Reduction of contamination at farm by a high level of biosecurity control and hygiene may be one of the most efficient ways to reduce the amount of contaminated poultry meat in Finland. Due to the low numbers of Campylobacter in the Finnish turkey production chain, enrichment PCR seems to be the optimal detection method here.

The impact of fluoroquinolone resistance of Campylobacter jejuni and Campylobacter coli isolates on the outcome of the disease in sporadic Campylobacter infections of Finnish individuals was studied. Questionnaires were sent, during a 6-month study period, to patients who were stool culture-positive for Campylobacter spp. In total, 192 returned questionnaires were analysed and assessed, together with the susceptibility data of the respective bacterial isolates. Only one (2%) of the domestic, but half of the imported, Campylobacter isolates were resistant to ciprofloxacin. Ciprofloxacin resistance was not associated with particularly severe infection. Instead, ciprofloxacin-susceptible Campylobacter isolates, as compared to ciprofloxacin-resistant isolates, showed a tendency to cause more severe infections, characterized by bloody stools and hospitalization.

Hippurate hydrolysis test results of 240 Campylobacter strains were compared with those of two multiplex polymerase chain reaction (PCR) assays. Of the 152 strains identified in Finnish clinical microbiology routine laboratories as C. coli (hippurate-negative), 11% were C. jejuni (hippurate-positive) by standardized hippurate test and 39% by PCR in the reference laboratory. Two of the 81 hippurate-positive strains were identified as C. coli. Standardizing the hippurate test by determining minimum and maximum turbidity limits (McFarland 6 and McFarland 10, OD(450) values 0.8 and 1.4, respectively) for the bacterial cell suspension eliminated the false-positive results, but 32% of the 145 hippurate-negative strains were still identified as C. jejuni by PCR. The species identification of Campylobacter isolates in Finland could be improved by using a standardized hippurate hydrolysis test to identify hippurate-positive C. jejuni and testing hippurate-negative strains by molecular methods. This would also improve the epidemiological data on this important zoonotic pathogen.

The study investigated the prevalence of Campylobacter spp. in Finnish cattle at slaughter and carcass contamination after slaughter. During the period January to December 2003, bovine rectal fecal samples (n=952) and carcass surface samples (n=948) from 12 out of 15 Finnish slaughterhouses were examined. In total, campylobacters were detected in 31.1% of fecal samples and in 3.5% of carcass surface samples. Campylobacter jejuni was isolated from 19.5%, Campylobacter coli from 2.2%, and presumptive Campylobacter hyointestinalis from 10.8% of fecal samples. Campylobacters were detected in 4.4% and 37.4% of the fecal samples examined both by direct culture and by enrichment (n=730), respectively, suggesting a low level of campylobacters in the intestinal content. A slightly increasing trend was observed in the overall prevalence of campylobacters towards the end of summer and autumn. Seventeen different serotypes were detected among the fecal C. jejuni isolates using a set of 25 commercial antisera for serotyping heat-stable antigens (Penner) of C. jejuni by passive hemagglutination. The predominant serotypes, Pen2 and Pen4-complex, were isolated from 52% of the fecal samples. Subtyping by pulsed-field gel electrophoresis (SmaI) yielded 56 and 20 subtypes out of 330 fecal and 70 carcass C. jejuni isolates, respectively. MICs of ampicillin, enrofloxacin, erythromycin, gentamicin, nalidixic acid, and oxytetracycline for 187 C. jejuni isolates were determined using a commercial broth microdilution method. Sixteen (9%) of the isolates were resistant to at least one of the antimicrobials tested. Resistance to nalidixic acid was most commonly detected (6%). No multiresistance was observed.

We describe a study on the application of multilocus sequence typing for the analysis of Campylobacter jejuni and C. coli isolates from human domestically acquired infections in the Helsinki-Uusimaa area of Finland in 1996, 2002, and 2003. In addition, isolates from poultry meat and fecal samples of cattle from the seasonal peak (July to September) in 2003 were included in the study. In total, 361 Finnish C. jejuni and C. coli strains were typed. Sequence type 45 (ST-45) (45%), ST-21 (21%), and ST-677 (11%) clonal complexes were the most prevalent. The ST-45 and ST-677 complexes were overrepresented in comparison with previous studies. The longitudinal study revealed an association between C. coli (ST-828 complex) infection and elderly patients (>/=60 years). Analysis of exposure factors, determined by a previous case-control study conducted during the seasonal peak in 2002, revealed that the ST-48 complex was significantly (P < 0.05) associated with the tasting or eating of raw minced meat. New and unassigned STs were associated with swimming in natural bodies of water, whereas the ST-677 complex was related to drinking nonchlorinated water from a small water plant or water from natural sources. The ST-45 complex was associated with contact with pet cats and dogs. In 2003, ST-45 occurrence was significantly associated with poultry whereas ST-50 was associated with isolates from humans. In contrast, ST-53, ST-58, ST-61, and ST-883 were significantly associated with isolates from cattle. Further studies are needed to reveal the significance of the observed associations.

Objectives: Although Campylobacter jejuni is naturally susceptible to fluoroquinolones, the resistance to these antimicrobials has increased rapidly during the recent years. The aim of this study was to compare the activities of various older and newer fluoroquinolones towards C. jejuni, with special attention on ciprofloxacin-resistant strains., Methods: We analysed the in vitro activities of 11 fluoroquinolones against 226 C. jejuni strains collected from Finnish patients between 1995 and 2000., Results: Of all 226 C. jejuni strains, 134 (59.3%) were resistant to ciprofloxacin (MIC > or = 4 mg/L), 1 (0.4%) was intermediately resistant (MIC = 2 mg/L) and 91 (40.3%) were ciprofloxacin-susceptible (MIC < or = 1 mg/L). The MIC50 and MIC90 values of ciprofloxacin for the 91 ciprofloxacin-susceptible strains were 0.25 and 0.5 mg/L, respectively. The corresponding MIC50 and MIC90 values of levofloxacin were 0.25 and 0.5 mg/L, and those of moxifloxacin were 0.125 and 0.25 mg/L, these being lower than those of norfloxacin and ofloxacin. The two newer fluoroquinolones, sitafloxacin and clinafloxacin, exhibited the lowest MIC50 and MIC90 values: 0.016 and 0.064 mg/L of sitafloxacin and 0.032 and 0.125 mg/L of clinafloxacin, respectively. Sitafloxacin and clinafloxacin exhibited the lowest MIC50 and MIC90 values also for the 134 ciprofloxacin-resistant C. jejuni strains: 0.25 and 1 mg/L of sitafloxacin and 1 and 4 mg/L of clinafloxacin, respectively., Conclusions: Of the newer fluoroquinolones presently under development, sitafloxacin is in vitro highly effective towards C. jejuni, with low MIC values also for the ciprofloxacin-resistant strains. Sitafloxacin might be a candidate for clinical trials on campylobacteriosis.

A matched case-control study was conducted to study risk factors for domestically acquired sporadic Campylobacter infections in Finland. Swimming in natural sources of water was a novel risk factor. Eating undercooked meat and drinking dug-well water were also independent risk factors for Campylobacter infection.

Study Objective: To determine the source and the extent of a community wide outbreak of gastroenteritis., Design: A matched case-control study with postal questionnaires. Subtyping of campylobacter strains by pulsed field gel electrophoresis (PFGE)., Setting: A rural municipality with a population of 8600 in southern Finland, August 2000. Two thirds of the population receive non-chlorinated ground water from the municipal water supply., Participants: Cases were randomly selected among residents of the municipality who contacted the municipal health centre because of gastroenteritis and had illness onset between 31 July and 20 August 2000. Community controls were identified from the population registry and matched according to sex, year of birth, and postal code., Main Results: Four hundred and sixty three persons contacted the municipal health centre because of gastroenteritis. Campylobacter jejuni was isolated from stool samples of 24 persons. One hundred and thirty seven cases and 388 controls were enrolled in the case-control study. In multivariate analysis, drinking unboiled water from the municipal supply was significantly associated with illness (odds ratio 11.1, 95% confidence interval 1.4 to 90.2). C jejuni was isolated from one tap water sample. The water isolate and all but one of the patient isolates were indistinguishable by PFGE., Conclusions: Combining epidemiological investigation with molecular subtyping methods provided strong evidence that water was the source of the outbreak. Non-chlorinated small ground water systems may be susceptible to waterborne outbreaks and constitute a risk to rural populations.

Objectives: The resistance of Campylobacter jejuni to fluoroquinolones is increasing globally. This study was performed to delineate those antimicrobial agents that are effective in vitro against ciprofloxacin-resistant C. jejuni isolates and potentially suitable for the treatment of severe disease when fluoroquinolone resistance or multidrug resistance is known or suspected., Methods: During 1995-2000 we collected 376 C. jejuni strains, of which 354 were of foreign origin from multiple countries and 22 were of domestic origin. The MICs of 12 antimicrobial agents against the isolates were determined., Results: Of the 376 strains, 174 (46%) were resistant to ciprofloxacin. Among other antimicrobials, resistance was most common to tetracycline (46%) and ampicillin (17%). Of the ciprofloxacin-resistant strains, 68% and 25%, respectively, were resistant to tetracycline and ampicillin, and 3% were resistant to erythromycin, gentamicin or clindamycin. One (0.6%) ciprofloxacin-resistant isolate was resistant to co-amoxiclav and none was resistant to imipenem. Resistance to three or more antimicrobial groups was detected in 22% of the isolates. Multidrug resistance was significantly associated with ciprofloxacin resistance (33% versus 12%; P<0.01). Eight (2%) strains were resistant to macrolides, of which 75% were also resistant to ciprofloxacin, but none was resistant to co-amoxiclav or imipenem., Conclusions: Macrolides still appear to be the first-choice alternative for suspected C. jejuni enteritis, if antimicrobial treatment is needed. The in vitro susceptibilities suggest that clinical trials to treat enteritis caused by multidrug-resistant C. jejuni with co-amoxiclav, and life-threatening infections with a carbapenem, may be valuable.

The association of Penner heat-stable serotypes and pulsed-field gel electrophoresis genotypes of 208 human and 30 chicken Campylobacter jejuni isolates was studied. Overall, 46% of the human strains had overlapping sero- and genotype combinations with chicken strains. The percentage was reduced to 31% for strains that were considered temporally related. This suggests common environmental sources.

Waterborne outbreaks associated with contamination of drinking water by Campylobacter jejuni are rather common in the Nordic countries Sweden, Norway, and Finland, where in sparsely populated districts groundwater is commonly used without disinfection. Campylobacters, Escherichia coli, or other coliforms have rarely been detected in potential sources. We studied three waterborne outbreaks in Finland caused by C. jejuni and used sample volumes of 4,000 to 20,000 ml for analysis of campylobacters and sample volumes of 1 to 5,000 ml for analysis of coliforms and E. coli, depending on the sampling site. Multiple samples obtained from possible sources (water distribution systems and environmental water sources) and the use of large sample volumes (several liters) increased the chance of detecting the pathogen C. jejuni in water. Filtration of a large volume (1,000 to 2,000 ml) also increased the rate of detection of coliforms and E. coli. To confirm the association between drinking water contamination and illness, a combination of Penner serotyping and pulsed-field gel electrophoresis (digestion with SmaI and KpnI) was found to be useful. This combination reliably verified similarity or dissimilarity of C. jejuni isolates from patient samples, from drinking water, and from other environmental sources, thus confirming the likely reservoir of an outbreak.

Ciprofloxacin resistance was analyzed in 354 Campylobacter jejuni isolates collected during two study periods (1995-1997 and 1998-2000) from travelers returning to Finland. The increase in resistance between the two periods was significant among all isolates (40% vs. 60%; p<0.01), as well as among those from Asia alone (45% vs. 72%; p<0.01).

The in vitro susceptibilities of 678 Campylobacter jejuni and Campylobacter coli strains isolated from stool samples of the same number of Finnish subjects were studied. A total of 523 patients, representing inhabitants from throughout Finland, had not traveled abroad within the 2 weeks prior to becoming ill, whereas 155 persons had presumably acquired their infections abroad. The antimicrobial agents studied were erythromycin, ciprofloxacin, levofloxacin, trovafloxacin, and moxifloxacin. The MICs of these antimicrobial agents were determined by the agar dilution method. The growth of all domestic isolates was inhibited by erythromycin at concentrations of 4 microg/ml, and for these isolates the fluoroquinolone MICs at which 90% of isolates are inhibited (MIC(90)s) ranged from 0.06 to 0.5 microg/ml. For the foreign isolates, the erythromycin MIC(90) was still low (4 microg/ml), but their susceptibilities to fluoroquinolones were clearly reduced (MIC(90)s, 8 to 64 microg/ml). Of the four different fluoroquinolones studied, ciprofloxacin was the least active (MIC(90), 64 micro g/ml).

Mutations in the quinolone resistance-determining region of the gyrA gene from 138 ciprofloxacin-resistant (MIC, > or =4 microg/ml) and 24 ciprofloxacin-susceptible (MIC, < or =1 microg/ml) clinical Campylobacter jejuni isolates were subjected to single-strand conformation polymorphism analysis and sequencing. All of the isolates could be assigned to three genotypic clusters based on silent mutations. All resistant isolates had a point mutation at codon 86.

Thirty-five Finnish Campylobacter jejuni strains with five SmaI/SacII pulsed-field gel electrophoresis (PFGE) genotypes selected among human and chicken isolates from 1997 and 1998 were used for comparison of their PFGE patterns, amplified fragment length polymorphism (AFLP) patterns, HaeIII ribotypes, and heat-stable (HS) serotypes. The discriminatory power of PFGE, AFLP, and ribotyping with HaeIII were shown to be at the same level for this selected set of strains, and these methods assigned the strains into the same groups. The PFGE and AFLP patterns within a genotype were highly similar, indicating genetic relatedness. The same HS serotypes were distributed among different genotypes, and different serotypes were identified within one genotype. HS serotype 12 was only associated with the combined genotype G1 (PFGE-AFLP-ribotype). These studies using polyphasic genotyping methods suggested that common Finnish C. jejuni genotypes form genetic lineages which colonize both humans and chickens.

A new commercial serotyping set based on heat-stable Penner's antigens was compared with pulsed-field gel electrophoresis (PFGE) with SmaI and SacII restriction endonucleases. Among 50 isolates of Campylobacter jejuni from Finnish patients, which represented predominant PFGE patterns selected from isolates from sporadic cases and isolates associated with small outbreaks, 11 different serotypes were demonstrated from 43 typable isolates. Several PFGE patterns could be found within one serotype; on the other hand, several serotypes could be demonstrated within one PFGE type. Most isolates originated from sporadic cases; however, some isolates were epidemiologically associated and showed identical serotypes and PFGE patterns. Although the new serotyping set would have been useful in the few epidemic cases studied, several isolates (14%) representing the major PFGE patterns remained untypable or gave weakly positive agglutination reactions only suggesting a plausible serotype (18%). This might restrict the use of the novel serotyping set, at least in Finland.

A total of 69 pulsed-field gel electrophoresis (PFGE) types were identified among 176 Campylobacter jejuni isolates from Finnish patients. In two geographic areas studied, five predominant PFGE types comprised over 40% of the isolates. One-third of the isolates had unique PFGE types. In small outbreaks, identical PFGE patterns were demonstrated, indicating a common source of infection.

The etiology of travelers' diarrhea was studied in 579 adult Finnish tourists participating in two packaged tours to Morocco in the winter (n = 233) and fall (n = 346) of 1989. A research team accompanied the travelers, and a laboratory for enteric pathogens was established in Agadir. At least one pathogen was found in 62% of the 60 diarrhea cases in winter and in 58% of the 111 diarrhea cases in fall. Multiple pathogens were found less often in winter (8%) than in fall (21%, P less than .05). Campylobacter strains were the leading cause of travelers' diarrhea in winter, found alone or with other pathogens in 28% of the cases (but in only 7% in fall), whereas enterotoxigenic Escherichia coli (ETEC) was the most common pathogen in fall, present in 32% of the cases (8% in winter). Both differences are highly significant (P less than .001). Salmonella enterica was almost as common as ETEC in fall (25% of diarrhea cases) but rare in winter (10%, P less than .05). Thus, the etiology of travelers' diarrhea varied according to the season in the same tourist destination. This finding has relevance to both antimicrobial treatment and prophylaxis.

The in vitro susceptibilities of 102 human campylobacter strains isolated between 1978 and 1980 and 100 strains isolated in 1990 to ciprofloxacin, norfloxacin, erythromycin, gentamicin, and doxycycline were examined. The biotypes and heat-stable serotypes of the strains as well as antimicrobial treatments and travel history of the campylobacter-positive patients were also studied. The results indicated that susceptibility to erythromycin, gentamicin, and doxycycline has remained the same during the past 10 years. No gentamicin-resistant strains were found. Resistance to erythromycin was 3% in both groups of strains. However, the number of norfloxacin-resistant strains increased from 4 to 11% in the follow-up period, and ciprofloxacin-resistant strains, which had not occurred 10 years ago, composed 9% of the strains isolated in 1990. Thus, the increase of fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli has been significant in Finland in the past 10 years.